1. Field of the Invention
The present invention relates to a handle assembly. More particularly, the present invention relates to a handle assembly for a lock.
2. Description of the Related Art
The outside handle of a conventional door lock could not be turned when in a locked state. However, the inner parts of the lock may be damaged after frequent tuning of the outside handle in the locked state. U.S. Pat. No. 6,705,138 discloses a clutch mechanism for a lock in which the outside handle rotates freely when the lock is in a locked state so that damage to the inner parts of the lock is avoided.
More specifically, as illustrated in FIG. 1 of the drawings, the lock disclosed in U.S. Pat. No. 6,705,138 includes an outside handle 31, an outside spindle 41 having an end fixed to the outside handle 31, a cam 42 received in an end of the outside spindle 41 and releasably engaged with a retractor 52 of a latch mechanism 5, a sleeve 43 received in the cam 42 and securely engaged with a locking bar 14 to turn therewith, and a lug 44 that is movable together with the cam 42 in a longitudinal direction and that is pivotally mounted around an end of the sleeve 43. When the locking bar 14 is moved inward to a locking position as a result of pushing a push button 15, the cam 42 is disengaged from the retractor 52 so that the outside handle 31 turns freely, preventing damage to the inner parts of the lock.
However, it was found that, after the outside handle 31 and the outside spindle 41 had been turned freely through a predetermined angle (typically 45 degrees or 60 degrees), further free rotation of the outside handle 31 was stopped by a lock housing comprised of an outside hub 33 and an inside hub 13, causing an impact to the outside handle 31 and the outside spindle 41. As a result, stress concentration occurred in the coupling area between the outside handle 31 and the outside spindle 41 that is relatively weak as compared to other parts of the lock, resulting in damage to or breakage of the outside spindle 41.
More specifically, referring to FIG. 1, the outside handle 31 is coupled with the outside spindle 41 by a spring-biased engaging plate 48 that extends in a plane orthogonal to the longitudinal direction of the outside spindle 41. The outside spindle 41 includes two holes 410a and 410b. A spring 47 is mounted between the engaging plate 48 and the outside spindle 41 for biasing the engaging plate 48 to a pre-determined position, with an end of the spring 47 extending out of the outside spindle 41 via one of the holes (e.g., hole 410a), and with the other hole 410b providing a space allowing inward movement of the engaging plate 48. The outside handle 31 includes a groove 311 for receiving an end of the engaging plate 48 when the outside handle 31 is mounted around the outside spindle 41, thereby positioning the outside handle 31.
Formation of the holes 410a and 410b weakens the outside spindle 41. Namely, the weakest portion of the outside spindle 41 is the place to which the engaging plate 48 is engaged. As a result, when the lock is in the locked state and when the outside handle 31 and the outside spindle 41 have been turned through a pre-determined angle, further rotational force applied to the outside handle 31 causes damage to and breakage of the outside spindle 41 at the weakest portion.
It is, therefor, a need for a reinforced handle assembly for a lock capable of preventing damage to the spindle resulting from a torque applied to a handle that has been turned through a pre-determined angle.